The present invention relates to a radial piston rotary power device and a drive mechanism particularly suited for the unique characteristics of such a rotary device.
Radial piston rotary engines are well known in the art and typically comprise a pair of pistons, each having two radial piston portions extending in diametrically opposite directions from a central axis. The diametrically opposed piston portions rotate as a unit about the central axis and each radial piston is connected to a piston shaft. The piston shafts are typically arranged in concentric fashion about the rotational axis of the pistons.
When the device operates as a power source, pressured gas may be introduced between closely adjacent piston portions of the two rotary pistons so as to exert a force thereon tending to rotate the pistons in opposite directions. Means are typically provided to ensure that both of the rotary pistons rotate in only a single direction. Therefore, one of the piston portions, typically termed the "lagging" piston, will either remain stationary or will rotate in the given direction at a relatively small angular velocity while the gases exert sufficient force on the other radial piston, typically termed the "leading" piston, causing it to rotate about the central axis at a higher angular velocity to rotate the associated piston shaft.
As the opposite piston portion of the "leading" piston approaches the stationary or slowly moving "lagging" piston, the rotary pistons assume opposite functions i.e. the previously "lagging" piston now becomes the "leading" piston, while the opposite portion of the previous "leading" piston now becomes the "lagging" piston. By introducing or pressurizing the gas between these piston portions, the new "leading" piston will rotate about its axis so as to rotate its piston shaft.
Although the rotary devices per se have proven to be a simple and efficient way of providing power, they have not achieved their maximum acceptance due to the difficulties encountered in converting the varying rotational speeds of the piston shafts into uniform rotational motion. Many systems have been devised and tried over the years including ring and pinion drives, cam drives, ratchet mechanisms, scissor crank drives and linkage mechanisms. While all of these drive systems are theoretically functional, they have proven to be unduly complex and inherently unreliable and inefficient. Despite the numerous attempts, the problem of simply and reliably converting the varying rotational speed of the two piston shafts into uniform rotation of a power shaft remains unsolved.